The present invention relates to novel dendrimeric compounds, to a method for the production thereof and to the use thereof as catalysts for the production of polymers, in particular to the use thereof as co-catalysts for metallocenes for polymerizing unsaturated compounds.
It has long been known to use metallocenes in combination with activating co-catalysts, preferably alumoxanes (MAOs), for polymerising olefins and diolefins (c.f. for example EP-A 129 368, 347 128, 347 129, 351 392, 485 821, 485 823).
However, catalyst systems based on metallocenes and alumoxanes have considerable disadvantages. Thus alumoxanes, in particular MAOs, cannot be produced with a high degree of reproducibility either in situ or in a pre-forming process. MAO is a mixture of various species containing aluminum which exist in equilibrium with each other, resulting in a loss of reproducibility during the polymerization of olefinic compounds. Moreover, MAO is not stable in storage and the composition thereof changes on exposure to extreme temperatures. Another serious disadvantage is the considerable excess of MAO which is necessary for the activation of metallocenes. However, this high MAO/metallocene ratio is an absolute prerequisite for achieving high catalyst activities. This results in a crucial processing disadvantage, however, since aluminum compounds must be separated from the polymers during work-up. Furthermore, MAO is a cost-determining factor in the use of catalyst systems containing MAO, meaning that excesses of MAO are uneconomic.
In J. Am. Chem. Soc. 1991, 113, 3623, tris(pentafluorophenyl)borane is described as a co-catalyst for metallocene dialkyls. However, the polymerisation activity of catalysts based on tris(pentafluorophenyl)borane is unsatisfactory. EP-A 277 003 and 277 004 describe ionic catalyst systems which are produced by the reaction of metallocenes with ionizing reagents. Perfluorinated, tetraaromatic borate compounds, in particular tetrakis(pentafluorophenyl)borate compounds, are used as ionizing reagents (EP 468 537, EP 561 479). However, the production and introduction of pentafluorophenyl substituents is complex and costly. Using tetrakis(pentafluorophenyl)borate compounds on an industrial scale is thus highly cost-intensive. Another disadvantage of tetrakis(pentafluorophenyl)borate compounds is the poor solubility thereof in hydrocarbons.
WO 93/11172 describes polyanionic activators for metallocenes which consist, for example, of a polystyrene matrix onto which what are termed non-coordinating anions, preferably borate compounds comprising pentafluorophenyl substituents, are chemically bonded. The catalytic activity of the borate compounds described above decreases considerably, however, if the fluoroaromatic substituents on the boron are replaced by other substituents, for example by methyl or butyl substituents.
In comparison with the activators described in EP 468 537, for example N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, the polyanionic activators (God described in WO 93/11172 exhibit lower polymerization activity. Another disadvantage is the poor yield during the production of the polyanionic activators. Costly tris(pentafluorophenyl)borane is used as a starting compound which must be chemically bonded by a complicated method onto a matrix, for example crosslinked polystyrene. The polyanionic activators do not have a uniform surface, wherein accessibility of the molecular surface or the active end groups may be restricted. The precise composition, in particular the number of active end groups of the polyanionic activators is not known. The polyanionic activators have neither a defined molecular size nor dimensional stability. The poor meterability of polyanionic activators is industrially disadvantageous. The sparingly soluble polyanionic activators are used as solids for catalysing polymerization, which is technically disadvantageous in a continuous polymerization process.
The object thus arose of identifying novel co-catalysts which avoid the above-stated disadvantages. In particular, the object consisted in creating a cost-effective catalyst system which is easy to produce, easy to handle industrially and is capable of polymerizing unsaturated compounds, such as for example olefins and dienes, at a high level of catalytic activity.
It has surprisingly now been found that dendrimeric compounds which contain metals, preferably in combination with metallocenes, are particularly suitable for achieving the above-stated objects.
The present invention accordingly provides novel dendrimeric compounds of the general formula
R14xe2x88x92iMe1[(R4)nX]ixe2x80x83xe2x80x83(I),
in which
X represents Me2R2R3(Ry)r,
R1, R2, R3, Ry are identical or different, may optionally be mono- or polysubstituted and represent hydrogen, C5-C20 cycloalkyl, C1-C20 alkyl, C7-C40 aralkyl, C6-C40 aryl, C1-C10 alkoxy, C6-C40 aryloxy, silyloxy or halogen,
R4 represents an optionally mono- or polysubstituted alkylene, alkenylene or alkynylene residue, which is optionally interrupted by one or more heteroatoms.
Me1 represents an element of group IVa of the periodic system of the elements (IUPAC nomenclature),
Me2 represents an element of group IIIa of the periodic system of the elements (IUPAC nomenclature),
i represents an integer from 2 to 4,
n represents an integer from 1 to 20 and
r represents 0 or 1
wherein, when r=1, the Me2 residue bears a negative formal charge and in the event of a negative formal charge on Me2, this is offset by a cation,
or in which
X represents Me1R5a[(R4)mMe2R2R3(Ry)r]3xe2x88x92a,
Me1, Me2, R1, R2, R3, R4, Ry, i, n, r have the above-stated meanings,
R5 has the meaning of the residues R1, R2, R3, Ry,
m is identical to or different from n and represents integers from 1 to 20 and
a represents 0, 1 or 2,
or in which
X represents Me1R5a[(R4)mMe1R6b[(R4)pMe2R2R3(Ry)r]3xe2x88x92b]3xe2x88x92a,
Me1, Me2, R2, R3, R4, Ry, i, n, r, m, a have the above-stated meanings,
R6 has the meaning of the residues R1, R2, R3, Ry, R5,
b represents 0, 1 or 2 and
p represents integers from 1 to 20,
xe2x80x83wherein the compounds described in DE 195 16 200 are excluded, said compounds being produced by the reaction of silicon tetrachloride in a Grignard reaction to form tetraallylsilane, which is subsequently reacted twice or more alternately
a) with trichlorosilane in a quantitative reaction in the presence of a catalyst and then
b) with an allyl compound in a Grignard reaction using a suitable solvent in each case until a dendrimeric skeleton comprising outwardly pointing allyl groups is obtained, the outer allyl groups of which
c) are derivatized in a hydroboration reaction with 9-borabicyclo[3.3.1]nonane.
Suitable cations in the event that Me2 bears a negative formal charge which may be considered are ions of atoms or molecules such as alkali metal ions, for example Li+, Na+ or K+, alkaline earth metal ions such as Be2+, Mg2+, Ca2+, Ba2+, transition metal ions such as Zn2+, Cd2+, Mg2+, Cu+, Cu2+, or organic compounds such as ammonium or phosphonium ions of the NR4+ or PR4+ type, preferably Phxe2x80x94N(CH3)2H+, or carbocations of the CR3+ type, preferably CPh3+.
The nature of the cation NR4+ in particular also has an influence on the solubility of the salts, consisting of the dendrimeric compounds according to the invention of the formula (I) which have at least one negative formal charge (r=1) and cations which offset the formal charge. The solubility of the stated salts in non-polar solvents, such as for example toluene and xylene, may, for example, be improved by using ammonium salts NRxe2x80x2R3+ which contain a relatively long-chain, branched or unbranched hydrocarbon residue Rxe2x80x2. Rxe2x80x2 is here preferably an unbranched C6-C40 alkyl residue, particularly preferably a C8-C12 alkyl residue. The remaining residues R in NR3Rxe2x80x2 may, mutually independently, be hydrogen and optionally mono- or polysubstituted C1-C5 alkyl and C6-C12 aryl residues. At least one residue R in NR3Rxe2x80x2 is preferably hydrogen. Specifically, cations such as undecyldimethylammonium and dodecyldimethylammonium may be mentioned.
Cycloalkyl residues in the formula (I) which may in particular be considered are those having 5 to 10 carbon atoms. Example which may be mentioned are cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl residues, fused cycloaliphatic residues such as decalin or hydrindene residues or bicyclic residues such as norbornyl residues.
Cyclopentyl, cyclohexyl and norbornyl residues are preferred.
Preferred alkyl residues are those having 1to 10 carbon atoms, the following being mentioned by way of example: methyl, ethyl, propyl, n-butyl, pentyl, hexyl, heptyl, octyl, isopropyl, sec.-butyl, tert.-butyl or neopentyl, preferably methyl, ethyl, propyl, n-butyl, sec.-butyl, tert.-butyl.
Aralkyl residues which may be mentioned arc those having 7 to 20 carbon atoms, preferably the benzyl residue.
Preferred aryl residues which may be considered are those having 6 to 20 carbon atoms, the following being mentioned by way of example: phenyl, toluyl, p-halophenyl, mesityl, pentafluorophenyl, bis(3,5-trifluoromethyl)phenyl, more preferably pentafluorophenyl, bis(3,5-trifluoromethyl)phenyl, most preferably pentafluorophenyl.
Aryloxy residues which may in particular be considered are those having 6 to 10 carbon atoms, phenyloxy residues being mentioned by way of example.
Silyloxy residues which may be considered are compounds of the type xe2x80x94Oxe2x80x94SiR3, in which R denotes C1-C10 alkyl residues or C6-C10 aryl residues. Silyloxy residues, such as xe2x80x94Oxe2x80x94SiMe3, xe2x80x94Oxe2x80x94SiEt3 and xe2x80x94Oxe2x80x94SiPh3, are preferred.
Examples of halogens which are used are fluorine, chlorine and bromine, in particular fluorine and chlorine.
As mentioned above, depending upon the number of C atoms, the residues R1, R2, R3, R4 and Ry of the formula (I) may be mono- or polysubstituted, preferably mono- to decasubstituted, particularly preferably mono- to pentasubstituted. Substituents which may be considered are, for example, the above-mentioned cycloalkyl, alkyl, aralkyl, aryl, alkoxy, aryloxy and silyloxy residues, as well as the stated halogens. Preferred substituents are halogens, in particular fluorine, alkyls, such as methyl and ethyl, perhalogenated alkyls, such as CF3, or perhalogenated aromatics, such as C6F5.
Elements of main group 4 of the periodic system of elements which may be mentioned are Si, Ge, Sn and Pb, preferably Si, Ge, Sn, in particular Si.
Elements of main group 3 of the periodic system of elements which may be considered are B, Al, In and Ga, preferably B, Al, very particularly preferably B.
In the formula (I), i preferably represents the numbers 3 or 4, particularly preferably 4, n is an integer from 1 to 10, in particular 2 to 5, and r represents 0.
In the formula (I), m furthermore preferably represents integers from 1to 10, in particular from 2 to 5, a represents 0, b represents 0 and p represents integers from 1 to 10, in particular 2 to 5.
Dendrimeric compounds which may be considered are preferably those of the formula (II)
R14xe2x88x92iSi[(R4)nX]ixe2x80x83xe2x80x83(II),
in which
X represents Me2R2R3(Ry)r, and R1, R2, R3, Ry are identical or different, preferably identical, may optionally be mono- or polysubstitluted, and represent C5-C6 Cycloalkyl, C6-C10 aryl, C1-C10 alkyl and/or halogen,
R4 represents a methylene residue,
Me2 represents boron or Al,
i represents an integer from 2 to 4,
n represents an integer from 1 to 20,
r may be 0 or 1,
or in which
X represents SiR5a[(R4)mMe2R2R3(Ry)r]3xe2x88x92a,
R5 has the meaning of the residues R1, R2, R3, Ry,
m is identical to or different from n and represents integers from 1 to 20,
a represents 0, 1 or 2,
and Me2, R2, R3, R4, i, n, r have the above-stated meanings,
or in which
X represents SiR5a[(R4)mSiR6b[(R4)pMe2R2R3(Ry)r]3xe2x88x92b]3xe2x88x92a,
Me2, R2, R3, R4, R5, Ry, i, n, r, m, a have the above-stated meanings, and
R6 has the meaning of the residues R1, R2, R3, R5, Ry,
b represents 0, 1 or 2 and
p represents integers from 1 to 20.
Particularly preferred dendrimeric compounds are those of the general formula (III)
R14xe2x88x92iSi[(CH2)nX]ixe2x80x83xe2x80x83(III),
in Which
X represents BR2R3(Ry)r and
R1, R2, R3, Ry are identical or different, preferably identical, may optionally be mono- or polysubstituted and represent C6-C10 aryl or C1-C10 alkyl,
i represents 3 or 4,
n represents 1 to 20 and
r represents 0 or 1
or in which
X represents SiR5a[(CH2)mBR2R3(Ry)r]3xe2x88x92a,
R5 has the meaning of the residues R1, R2, R3, Ry,
m is identical to or different from n and represents integers from 1 to 20,
a represents 0, 1 or 2 and
R2, R3, R5, Ry, i, n, r have the above-stated meanings,
or in which
X represents SiR5a[(CH2)mSiR6b[(CH2)pBR2R3(Ry)r]3xe2x88x92b]3xe2x88x92a,
R2, R3, R5, Ry, i, n, r, m, a have the above-stated meanings,
R6 has the meaning of the residues R1, R2, R3, Ry,
b represents 0, 1 or 2 and
p represents integers from 1 to 20.
Emphasis should be placed upon the dendrimeric compounds of the following formulae:
Si[(CH2)3BCl2]4 
Si[(CH2)3BMe2]4 
Si[(CH2)3B(C6F5)2]4 
Si[(CH2)3BMes2]4 
Si[(CH2)3B(C6H3(CF3)2)2]4 
Si[(CH2)3BMe3]44xe2x88x924K+
Si[(CH2)3B(n-Bu)3]44xe2x88x924K+
Si[(CH2)3B(n-Bu)2]4 
Si[(CH2)3B(C6F5)3]44xe2x88x924K+
Si[(CH2)3B(C6H3(CF3)2)3]44xe2x88x924K+
Si{(CH2)2Si[(CH2)3BCl2]3}4 
Si{(CH2)2Si[(CH2)3BMe2]3}4 
Si{(CH2)2Si[(CH2)3B(n-Bu)2]3}4 
Si{(CH2)2Si[(CH2)3B(C6F5)2]3}4 
Si{(CH2)2Si[(CH2)3BMe3]3}412xe2x88x9212K+
Si{(CH2)2Si[(CH2)3B(n-Bu)3]3}412xe2x88x9212K+
Si{(CH2)2Si[(CH2)3B(C6F5)3]3}412xe2x88x9212K+
Si{(CH2)2Si[(CH2)3B(3,5-(CF3)2C6H3)3]3}412xe2x88x9212K+
Si{(Oxe2x80x94CH2)3Si(CH3)[(CH2)3BCl2]2}4 
Si{(Oxe2x80x94CH2)3Si(CH3)[(CH2)3BMe2]2}4 
Si{(Oxe2x80x94CH2)3Si(CH3)[(CH2)3B(n-Bu)2]2}4 
Si{(Oxe2x80x94CH2)3Si(CH3)[(CH2)3B(C6H5)2]2}4 
Si{(Oxe2x80x94CH2)3Si(CH3)[(CH2)3B(C6F5)2]2}4 
Si{(Oxe2x80x94CH2)3Si(CH3)[(CH2)3BMe3]44xe2x88x924K+
Si{(Oxe2x80x94CH2)3Si(CH3)[(CH2)3B(C6H5)3]44xe2x88x924K+
Si{(Oxe2x80x94CH2)3Si(CH3)[(CH2)3B(C6F5)3]44xe2x88x924K+
wherein Mes represents 2,4,6-mesityl and K means a cation bearing one or more charges.
K preferably represents alkali metal ions, such as for example Li+, Na+, K+ or carbenium ions, such as for example the triphenylmethyl cation or di- or trisubstituted ammonium ions, such as for example N,N-dimethylanilinium, trimethylammonium, triethylammonium, tri(n-butyl)ammonium, dimethylundecylammonium, dimethyldodecylammonium, dimethyloctadecylammonium, methyldioctadecylammonium, methyloctadecylammonium or dioctadecylammonium ions.
The present invention also provides a method for the production of dendrimeric compounds of the general formula (I), which method is characterized in that compounds of the general formula (IV)
R14xe2x88x92iMe1[(R7)nxe2x88x922Y]ixe2x80x83xe2x80x83(IV)
in which
Y represents CR8=CR9R10,
R8, R9 and R10 are identical or different and represent hydrogen, alkyl, aryl or halogen,
R7 has the meaning of residue R4 in the formula (I) and
n represents an integer from 2 to 20,
R1, Me1 and i have the definition stated for the formula (I),
or in which
Y represents Me1R5a[(R7)mxe2x88x922(CR8=CR9R10)]3xe2x88x92a,
R5 has the definition""stated in the formula (I),
or in which
Y represents Me1R5a[(R4)mMe1R6b[(R7)pxe2x88x922(CR8xe2x95x90CR9R10)]3xe2x88x92b]3xe2x88x92a,
R6 has the definition stated in formula (I),
m, p represent an integer from 2 to 20 and in which all the other residues stated in the formulae have the above-stated meanings for Y,
are reacted with compounds of the general formula (V)
R11Me2R2R3xe2x80x83xe2x80x83(V),
in which
R11represents hydrogen or C1-C30 alkyl and
Me2, R2 and R3have the meanings stated in the formula (I),
xe2x80x83and, in the event that r=1, the resultant product is further reacted with compounds of the general formula (VI)
Me3xe2x80x94Ryxe2x80x83xe2x80x83(VI),
in which
Me3 represents an alkali metal and Ryhas the meaning stated in the formula (I),
or with compounds of the general formula (VII)
Halqxe2x80x94Me4xe2x80x94Ry2xe2x88x92qxe2x80x83xe2x80x83(VII),
in which
Me4 represents an alkaline earth metal or transition metal of subgroups 1 or 2,
Hal represents halogen,
q represents 0 or 1 and
Ry has the meaning as before.
The preferred alkaline earth metal is Mg, with the preferred transition metals being Zn, Cd, Hg or Cu. Preferred alkali metals are Li, Na and K, particularly preferably Li.
Hydrogen and C1-C5 alkyl are preferred as residues R8, R9 and R10, with hydrogen being particularly preferred.
The influence of the metal atom Me1in unsaturated compounds of the formula (IV) in which n, m or p=2 often results, during addition of compounds of the formula (V), in the formation of branched compounds having the following structural element 
as a result of which compounds of the formula (I) in which n, m or p=1 may be obtained.
Compounds of the formulae (IV), (V), (VI) and (VII) which are preferably used are respectively those of the general formulae (IVa), (Va), (VIa) and (VIIa) shown below:
R14xe2x88x92iSi[(CH2)nY]ixe2x80x83xe2x80x83(IVa)
in which
Y represents xe2x80x94CHxe2x95x90CH2,
i represents 3 or 4,
R1 represents an optionally mono- or polysubstituted C1-C6 alkyl or C6-C12 aryl residue and
n represents an integer from 1 to 10,
or in which
Y represents SiR5a[(CH2)m(CHxe2x95x90CH2)]3xe2x88x92a,
a represents 0, 1 or 2 and
R5 has the meaning of R1,
m represents an integer from 1 to 10,
or in which
Y represents SiR5a[(CH2)mSiR6b[(CH2)pCHxe2x95x90CH2]3xe2x88x92b]3xe2x88x92a,
R6 has the meaning of R1 and
p and m represent an integer from 1 to 10;
Hxe2x80x94BR2R3xe2x80x83xe2x80x83(Va),
in which
R2 R3 have the meaning stated in the formula (I);
Me3xe2x80x94Ryxe2x80x83xe2x80x83(VIa),
in which
Me3 represents Li or Na and
Ry has the meaning stated in the formula (I);
Halqxe2x80x94Mgxe2x80x94Ry2xe2x88x92qxe2x80x83xe2x80x83(VIIa),
in which
Hal represents Cl or Br and
Ry has the meaning as in formula (I) and
q represents 0 or 1.
Compounds of the formula (IV) which are particularly preferably used are those of the general formula IVb):
Si[(CH2)nY]4xe2x80x83xe2x80x83(IVb)
in which
Y represents xe2x80x94CHxe2x95x90CH2 and
n represents 1, 2, 3 or 4,
or in which
Y represents Si[(CH2)mCHxe2x95x90CH2]3 and
m represents 1, 2, 3 or 4,
or in which
Y Si[(CH2)mSi[(CH2)pCHxe2x95x90CH2]3]3,
p represents 1, 2, 3 or 4 and
m has the above meaning.
As mentioned above, in the method according to the invention, compounds of the general formula (IV) are reacted with compounds of the general formula (V) and in this manner nonionic dendrimeric compounds of the general formula (I) where r=0 are obtained.
According to the invention, the compounds of the general formula (IV) are reacted with compounds of the general formula (V) at temperatures of xe2x88x92100 to 150xc2x0 C., preferably of xe2x88x9280 to 100xc2x0 C., and at pressures from standard pressure to 10 bar, preferably at standard pressure. The molar ratio of compounds of the general formula (IV) to compounds of the general formula (V) during the reaction is generally such that at least one equivalent of the compound of the formula (V) is available for each residue CR8xe2x95x90CR9R10 of the formula (IV).
The reaction is optionally performed in the presence of solvents and/or diluents, such as for example alkanes. In many cases, however, it is also possible to dispense with the use of solvents and/or diluents. This is the case, for example, if an unsaturated compound of the formula (IV) is reacted with HBCl2. The necessary HBCl2 may, for example, be produced during the reaction as an intermediate from trialkylsilanes, R3Sixe2x80x94H and BCl3. This method of preparation is described, for example, in J. Org. Chem. 1990, 55, 2274.
In order to produce dendrimeric compounds of an ionic structure of the general formula (I) (in the event that r=1), the reaction product obtained from compounds of the general formula (IV) and compounds of the general formula (V) is further reacted with organic alkali metal, alkaline earth metal or transition metal compounds of the formula (VI) or (VII).
The reaction proceeds in this case at temperatures of xe2x88x92100 to +200xc2x0 C. and standard pressure, preferably at xe2x88x92100 to 150xc2x0 C. Solvents and/or diluents which may be considered are those stated above in the quantities which have likewise been stated above.
The compounds of the formulae (VI) or (VII) are preferably used in an equimolar ratio or an excess relative to the residue Me2R2R3 of the dendrimeric compounds of the formula (I) where r=0 obtained from the reaction of compounds of the formula (IV) with compounds of the formula (V).
Production of the starting compounds of the formula (IV) is known and may proceed in a similar manner to the production of carbosilane dendrimers. Instructions for the production of carbosilane dendrimers may be found, for example, in Rubber Chem. Technol. 1992, 65, 303-314, Adv. Mater. 1993, 5, 466-468, Macromolecules 1993, 26, 963-968, J. Chem. Soc., Chem. Commun. 1994, 2575-2576, Organometallics 1994, 13, 2682-2690, Macromolecules 1995, 28, 6657-6661 and Organometallics 1995, 14, 5362-5366.
During such production, an alkenylsilane, such as for example tetravinyl- or tetrallylsilane, is reacted with a hydrochlorosilane, such as HSiCl3, MSiMeCl2 or MSiMe2Cl, and the resultant product is further reacted with an alkenylmagnesium compound (Grignard reaction). This reaction sequence (hydrosilylation with a Grignard reaction) may be repeated twice or more.
Preferred starting compounds of the formula (IV) which may be considered are: 
Production of the compounds of the formula (I) according to the invention may be illustrated by the following reaction scheme: 
The novel dendrimeric compounds of the formula (I) may be used as catalysts or for the production of catalyst systems based on transition metal complexes. The stated use of the compounds of the formula (I) according to the invention is not restricted by the appended condition included in the formula (I).
Catalyst systems based on transition metal complexes and the stated dendrimeric compounds of the unrestricted formula (I) consist, for example, of
a) a transition metal complex of the formula (VIII)
AcMe5R12dxe2x80x83xe2x80x83(VIII),
xe2x80x83in which
Me5 represents a transtion metal of groups IIIb to VIIb or of group VIII of the periodic system of elements according to IUPAC nomenclature,
A represents an optionally singly- or multiply bridged anionic ligand
R12 has the same meaning as R1, and
c, d represent an integer from 0 to 6 and
b) a dendrimeric compound of the formula (I),
wherein the molar ratio of component a) to component b) is conventionally in the range from 1:0.01-1:100, preferably from 1:0.1-1:1.
Transition metal complexes of the formula (VIII) which may in particular be considered are those in which
Me5 is an metal from the group titanium, zirconium, hafnium, vanadium, niobium and tantalum,
A is a pyrazolate of the formula N2C3R133 
a pyrazolylborate of the formula R14B(N2C3R133)3,
an alkoxide or phenolate of the formula OR14,
a siloxane of the formula OSiR143,
a thiolate of the formula SR14,
an acetylacetonate of the formula (R14CO)2CR14,
a diimine of the formula (R15Nxe2x95x90CR14)2,
an amidinate of the formula R14C(NR152)2,
a cyclooctatetraenyl, an optionally mono- or polysubstitulted cyclopetitadienyl, an optionally mono- or polysubstituted indenyl and an optionally mono- or polysubstituted fluorenyl, wherein substituents which may be considered are a C1 to C20 alkyl group, a C1-C10 alkoxy group, a C6 to C20 aryl group, a C6 to C10 aryloxy group, a C7 to C40 arylalkyl group, a C7-C40 alkylaryl group, a boranyl, silyl, amino or phosphinyl group optionally substituted by C1 to C10 hydrocarbon residues,
R12 represents hydrogen, fluorine, chlorine, bromine, methyl, benzyl, neopentyl and phenyl,
R13 in the formulae for A represents hydrogen or a C1-C10 alkyl group,
R14, R15 in the formulae for A have the same meaning as R1,
c represents 1 or 2 and
d represents 2 or 3.
Preferred transition metal complexes of the formula (VIII) are those in which
Me5 represents titanium, zirconium and hafnium,
A represents bis(trimethylsilyl)amide, dimethylamide, diethylamide, diisopropylamide, 2,6-di-tert.-butyl-4-methylphenolate, cyclooctatetraenyl, cyclopentadienyl, methylcyclopentadienyl, benzylcyclopentadienyl, n-propylcyclopentadienyl, n-butylcyclopentadienyl, isobutylcyclopentadienyl, t-butylcyclopentadienyl, cyclopentylcyclopentadienyl, octadecylcyclopentadienyl, 1,2-dimethylcyclopentadienyl, 1,3-dimethylcyclopentadienyl, 1,3-diisopropylcyclopentadienyl, 1,3-di-t-butylcyclopentadienyl, 1-ethyl-2-methylcyclopentadienyl, 1-isopropyl-3-methylcyclopentadienyl, 1-(n-butyl)-3-methylcyclopentadienyl, 1-(t-butyl)-3-methylcyclopentadienyl, pentamethylcyclopentadienyl, 1,2,3,4-tetra-methylcyclopentadienyl, 1,2,4-trimethylcyclopentadienyl, 1,2,4-triisopropylcyclopentadienyl, 1,2,4-tri-(t-butyl)cyclopentadienyl, indenyl, tetra-hydroindenyl, 2-methyl indenyl, 4,7-dimethylindenyl, 2-methyl-4,5-benzoindenyl, 2-methyl-4-phenylindenyl, fluorenyl or 9-methylfluorenyl,
R12 represents chlorine, methyl or benzyl,
c represents 1 or 2 and
d represents 2 or 3,
and the anionic ligands A may be bridged by divalent groups such as Me2Si, Ph2Si, Ph(Me)Si, Me2C, Ph2C, Ph(Me)C or CH2CH2. Examples of the stated transition metal compounds in which c=2 are described, inter alia, in EP 129 368, EP 351 392, EP 485 821, EP 485 823, EP 549 990, EP 659 758. Examples of the stated transition metal compounds in which c=1 are described, inter alia, in Macrormol. Chem. Rapid Conimun. (13) 1992, 265 and, in the case of bridged monocyclopentadienyl complexes, in EP 416 815, WO 91/04257 or WO 96/13529.
Further transition metal complexes of the formula (VIII) which may be considered are those in which
Me5 represents nickel and palladium,
A represents a diimine of the formula (R15Nxe2x95x90CN14)2,
c represents 1 and d represents 2,
and R12, R14, R15 have the above-stated meaning.
Examples of the stated diimine complexes are described, inter alia, in WO 96/23010.
Organoaluminum compounds may optionally additionally be added to the catalyst system comprising transition metal complexes and the dendrimers according to the invention. Examples of organoaluminium compounds are trialkylaluminum compounds, such as trimethylaluminium, triethylaluminum, triisobutlaluminum, triisooctylaluminum as well as dialkylaluminum compounds, such as diisobutyllaluminum hydride, or aluminoxanes, such as trimethylaluminoxane or triisobutylaluminoxane. The molar ratio of the organoaluminum compounds to transition metal complexes of the formula (VIII) is in the range from 10000:1-0.1:1, preferably from 1000:1-1:1, particularly preferably from 100:1-10:1.
The present invention also provides the use of the novel catalysts or catalyst systems for the polymerization of unsaturated organic compounds, in particular of olefins and dienes. Polymerization is here taken to mean both homo- and copolymerization of the stated unsaturated compounds. C2-C10 alkenes, such as ethylene, propylene, 1-butene, 1-pentene and 1-hexene, 1-octene, isobutylene and arylalkenes, such as styrene, are in particular used in said polymerization. Dienes which are in particular used are: conjugated dienes, such as 1,3-butadiene, isoprene, 1,3-pentadiene, and unconjugated dienes, such as 1,4-hexadiene, 1,5-heptadiene, 5,7-dimethyl-1,6-octadiene, 4-vinyl- 1-cylohexene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene and dicyclopentadiene.
As mentioned above, however, the novel dendrimeric compounds of the formula (I) may also be used on their own as catalysts, for example for polymerization reactions. The dendrimeric compounds of the formula (I) are suitable not only for polymerizing unsaturated compounds, but also for polymerizing cyclic ethers, such as ethylene oxide, propylene oxide and tetrahydrofuran.
The catalysts according to the invention are in particular suitable for the production of rubbers based on copolymers of ethylene with one or more of the stated xcex1-olefins and the stated dienes. The catalyst system according to the invention is furthermore suitable for polymerizing cycloolefins, such as norbomene, cyclopentene, cyclohexene or cyclooctane and for copolymerizing cycloolefins with ethylene or xcex1-olefins.
Polymerization may be performed in the liquid phase, in the presence or absence of an inert solvent, or in the gas phase. Suitable solvents are aromatic hydrocarbons, such as benzene and/or toluene, or aliphatic hydrocarbons, such as propane, hexane, heptane, octane, isobutane, cyclohexane, or mixtures of the various hydrocarbons.
It is possible to use the catalyst system according to the invention applied onto a support. Suitable support materials which may be mentioned are, for example, inorganic or organic polymeric supports, such as silica gel, magnesium chloride, zeolites, carbon black, activated carbon, aluminum oxide, polystyrene and polypropylene.
Polymerization is generally performed at pressures of 1 to 1000, preferably of 1 to 100 bar, and temperatures of xe2x88x92100xc2x0 C. to +250xc2x0 C., preferably of 0xc2x0 C. to +150xc2x0 C. Polymerization may be performed continuously or discontinuously in conventional reactors.
The novel dendrimeric compounds of the formula (I) are distinguished by elevated thermal stability and storage stability. They are produced from inexpensive educts which are industrially available in large quantities. The production method described above provides wide scope for various structural variants of the dendrimeric compound of the formula (I), which have a defined molecular structure. The optimum structure may accordingly be tailored to the intended application.
In combination with transition metal complexes of the formula (VIII), the novel dendrimeric compounds have elevated catalytic activity for the polymerization of unsaturated compounds. They moreover have improved catalyst service lives, i.e. consistently high catalytic activity over extended periods of polpymerization. Due to their elevated catalytic activity, only small quantities of the dendrimeric compounds are required. The residual catalyst content in the polymer is so low that no work-up is required to remove the catalyst. This gives rise to a processing advantage as a costly washing step to remove the catalyst is omitted.
Another advantage is the favourable molar ratio of transition metal complexes of the formula (VIII) to dendrimeric compounds of the formula (I) in the production of catalyst system. Highly reproducible catalytic activities are obtained if the dendrimeric compounds are used in a molar deficit relative to the transition metal complex.
No preactivation is required when the dendrimeric compounds of the formula (I) are used to produce catalyst systems. For example, olefins may be polymerized as follows: after the conventional cleaning operations, a steel autoclave is filled with a solvent and a scavenger, for example triisobutyaluminum. The scavenger renders harmless any possible contaminants and catalyst poisons, for example water or other compounds containing oxygen. A compound of the formula (VIII) is then added as a catalyst precursor. The reactor is then filled with monomers and polymerization is started by adding a solution of the dendrimeric compounds described above. Separate feeding of the dendrimeric compound without preactivation is of particular advantage in a continuous polymerization process.
The invention is illustrated in greater detail by the following Examples.
The organometallic compounds were produced and handled under a protective argon atmosphere and with the exclusion of air and moisture (Schlenk technique). All the necessary solvents were obtained in absolute form before use by boiling for several hours over a suitable desiccant and subsequent distillation under argon. The compounds were preferably characterized by 11B NMR, optionally also by 1H NMR and 13C NMR. Other commercial educts were used without further purification. Tetraallylsilane was produced from silicon tetrachloride and allylmagnesium chloride.